Abaixo está uma instrução que descreve uma tarefa de geração de SQL, combinada com uma entrada que fornece mais contexto sobre os esquemas de tabela disponíveis. Escreva o código SQL que responda adequadamente à solicitação
 ###Instrução: Qual é o número de tentativas contra, quando os pontos contra são 213?
 ###Tabelas: CREATE TABLE round_4 (round_4_id AUTO_INCREMENT PRIMARY KEY, Home team VARCHAR, Home team score VARCHAR, Away team VARCHAR, Away team score VARCHAR, Venue VARCHAR, Crowd INT, Date VARCHAR) CREATE TABLE caucuses (caucuses_id AUTO_INCREMENT PRIMARY KEY, Candidate VARCHAR, State Delegate INT, Percentage VARCHAR, Delegates INT, Counties Carries INT) CREATE TABLE atp_tour_career_earnings (atp_tour_career_earnings_id AUTO_INCREMENT PRIMARY KEY, Year INT, Majors INT, ATP wins INT, Total wins INT, Earnings ($) INT, Money list rank INT) CREATE TABLE number_of_championships_by_school (number_of_championships_by_school_id AUTO_INCREMENT PRIMARY KEY, University VARCHAR, Men's INT, Women's INT, Runner-up INT, Total Championships INT) CREATE TABLE pool_2 (pool_2_id AUTO_INCREMENT PRIMARY KEY, Team VARCHAR, Tries for VARCHAR, Tries against VARCHAR, Try diff VARCHAR, Points for VARCHAR, Points against VARCHAR, Points diff VARCHAR)  
SELECT Tries against FROM pool_2 WHERE Points against = 213